title: On the segregative tendency of ethoxylated surfactants in nonionic mixed micelles.
abstract: The aqueous mixtures of two nonionic surfactants, pentaethyleneglycol monohexyl ether (C(6)E(5)) and hexyl dimethyl phosphine oxide (C(6)DMPO), were investigated by the pulsed-gradient stimulated-echo NMR technique. Quite unexpectedly, the results show that the mixture behavior significantly deviates from ideality. Particularly, analysis of the data indicates that, in the mixed aggregates, C(6)E(5) molecules prefer to be surrounded by other C(6)E(5) molecules, forming domains of hydrated ethoxilic chains on the micellar surface. Molecular reasons for the segregative tendency of ethoxylated surfactants and its applicative implications in formulation technology are discussed.
authors.affiliation: Dipartimento di Chimica, Università di Napoli Federico II, Complesso di Montesantangelo, via Cinthia, 80126 Napoli, Italy. gerardino.derrico@unina.it
authors.forename: Gerardino
authors.initials: G
authors.lastname: D'Errico